Fuc Alpha 1-2Gal Beta Research Articles

A novel sialylfucopentaose in human milk. Presence of this oligosaccharide is not dependent on expression of the secretor or Lewis fucosyltransferases.

We have identified a novel oligosaccharide in human milk that is a fucosyl derivative of sialyltetrasaccharide c (NeuAc alpha 2-6Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc). This oligosaccharide was purified by affinity chromatography on a column of immobilized Ricinus communis I lectin. Structural analyses of radiolabeled oligosaccharides by exoglycosidase digestions, binding by specific anti-carbohydrate antibodies, and analysis of the 3H-labeled glucitol derivative obtained after permethylation and hydrolysis are consistent with the following proposed structure. (formula; see text) The analyses of human milk sialylpentasaccharides from donors typed as Le(a-,b+), Le(a+,b-), and Le(a-,b-) secretor confirmed the secretor gene-dependent expression of the sialylated lacto-N-fucopentaose I (Fuc alpha 1-2Gal beta 1-3[NeuAc alpha 2-6]GlcNAc beta 1-3Gal beta 1-4Glc) and the Lewis gene-dependent expression of the sialylated lacto-N-fucopentaose II (NeuAc alpha 2-3Gal beta 1-3[Fuc alpha 1-4]GlcNAc beta 1-4Glc). However, the presence of this novel oligosaccharide in human milk is not dependent on the expression of either the secretor gene or the Lewis gene-specified fucosyltransferases.

A monoclonal antibody that precipitates the glycoprotein receptor for epidermal growth factor is directed against the human blood group H type 1 antigen.

Monoclonal antibody 101 produced by a hybridoma obtained by fusion with NS-1 myeloma cells of spleen cells from a mouse immunized with the human epidermoid carcinoma cell line, A431, specifically precipitates epidermal growth factor receptor, a glycoprotein of 170,000 Mr solubilized from A431 cell membranes (Richert, N. D., Willingham, M. C., and Pastan, I. H. (1983) J. Biol. Chem. 258, 8902-8907). The antibody also binds to neutral glycolipids extracted from A431 cells as evidenced by solid phase radioimmunoassay and by autoradiography. Binding of antibody to its target is inhibited by lacto-N-fucopentaose I but not by 2'-fucosyllactose or related oligosaccharides. Thus, antibody 101 is probably directed against the human blood group H type 1 sugar sequence Fuc alpha 1-2Gal beta 1-3GlcNAc . . .. This sequence presumably occurs on the epidermal growth factor receptor. Monoclonal antibody 102 produced by another hybridoma from the same fusion has the same cell specificity as antibody 101 and also binds to neutral glycolipids. However, binding of antibody 102 to its target is inhibited by 2'-fucosyllactose and not by lacto-N-fucopentaose I or related oligosaccharides. Thus, antibody 102 is probably directed against the human blood group H type 2 sugar sequence Fuc alpha 1-2Gal beta 1-4GlcNAc . . .. Antibody 102 does not precipitate solubilized epidermal growth factor receptor. Both antibodies bind to neutral glycolipids extracted from human erythrocytes belonging to blood group O but not to neutral glycolipids extracted from human erythrocytes with the "Bombay" phenotype.

Structural characterization of neutral oligosaccharides of human midcycle cervical mucin.

It was previously shown that alkaline borohydride treatment of human midcycle cervical mucin releases a heterogeneous population of reduced neutral, sialylated, and sulfated oligosaccharides (Yurewicz, E. C., and Moghissi, K. S. (1981) J. Biol. Chem. 256, 11895-11905). Three major neutral oligosaccharides were isolated with approximate compositions of Fuc:Gal:GlcNAc:N-acetylgalactosaminitol (GalNAcol) = 0:2:1:1 (A1), 1:2:1:1 (A2), and 2:2:1:1 (A3). They comprised roughly 21%, 13%, and 8% of human cervical mucin oligosaccharide chains, respectively. In the present report, each was analyzed by periodate oxidation, methylation, and sequential degradation with glycosidases. A1 was shown to contain more than one component, but structural analyses clearly demonstrated the presence of one predominant (75%) tetrasaccharide. The proposed structure, Gal beta 1-4GlcNAc beta 1-6(Gal beta 1-3)GalNAcol, has previously been found in human gastric, submaxillary, and ovarian cyst mucins in their carbohydrate-to-protein linkage regions. beta-Galactosidase from Aspergillus niger selectively cleaved the Gal beta 1-4GlcNAc linkage in the intact tetrasaccharide. Enzymatic hydrolysis of the Gal beta 1-3GalNAcol linkage required prior removal of the Gal beta 1-4GlcNAc beta 1-unit attached to 0-6 of GalNAcol. The data for A2 indicated a mixture of two oligosaccharides, Gal beta 1-4,3(Fuc alpha 1-3,4)GlcNAc beta 1-6(Gal beta 1-3)GalNacol and Fuc alpha 1-2Gal beta 1-4GlcNac beta 1-6(Gal beta 1-3)-GalNacol, in an approximate molar ratio of 3 to 4:1, respectively. Two structures are consistent with the data obtained for A3: Fuc alpha 1-2Gal beta 1-4,3(Fuc alpha 1-3,4)GlcNAc beta 1-6(Gal beta 1-3)GalNAcol and/or Gal beta 1-4,3(Fuc alpha 1-3,4)GlcNac beta 1-6(Fuc alpha 1-2Gal beta 1-3)GalNacol. The results indicate that A1 represents the "core" tetrasaccharide of the larger human cervical mucin oligosaccharides A2 and A3.